Novel sleep mode control mechanism for energy efficient TDM passive optical networks

Abstract

Passive Optical Networks (PONs) are considered to be one of the energy efficient access technologies. Initially, when some of the PON systems (e.g. Time Division Multiplexing (TDM)-PON) were standardized (e.g. IEEE 802.3ah, IEEE 802.3av) it was recommended that an Optical Network Unit (ONU), which is installed at the user premises, should be always on. However, some statistics show that access network equipments (e.g. an ONU) have a utilization around 15\%. This indicates that there is a still room to improve energy efficiency in TDM-PONs (Ethernet PON (EPON), Gigabit PON (GPON)). One of the common and efficient approaches to maximize energy efficiency in a TDM-PON is to put an ONU in sleep mode turning off some of its power hungry components while it does not have any traffic to receive and/or transmit. However, the length of sleep interval plays a significantly important role on energy efficiency of an ONU and traffic delay. That is, there exists a very strong trade off relationship. If the length of sleep interval is increased, there would be less energy consumption at an ONU; however, the traffic will experience longer delay, and the other way around. The important fact is that improving energy efficiency in network equipments is increasingly important issue in today`s research as they are largely contributing on increasing the carbon footprint. However, as mentioned above that energy saving and traffic performance introduce a trade off relationship. Then, rationally, an PON operator cannot lose revenue just for the sake of saving energy. Therefore, a novel solution is required that will be able to save energy in ONUs and provide desired traffic performance at the same time. As the penetration rate of TDM-PONs are much higher than other PON solutions (e.g. wavelength division multiplexing PON (WDM-PON)), the research contributions presented in this dissertation consider TDM-PON environment. In this dissertation, a novel Adaptive Delay-Aware Energy Efficien...